As part of a program to reduce electrical energy consumption in the refining process, the effects of alkaline peroxide treatments on second stage thermomechanical pulp properties before and after low consistency refining have been investigated. The low consistency refining stage was simulated using a "Waring Blendor". Highly alkaline peroxide treatments resulted in gains in pulp properties that would allow reduced energy input in second-stage refining. The treated pulp was more flexible and more resistant to cutting during subsequent low consistency refining. The improved properties resulted mainly from production of acid groups on the fibre surface or in the fines.